Various solutions have been attempted to direct light into a desired beam angle. Condenser lenses have been used in the illumination industry to collect light for centuries. The drawback of condenser lenses is that they have relatively low collection NA. As LEDs have become more prevalent in the illumination industry, new optics have been developed to shape the light beam. The majority of these rely on reflection to control the light distribution. Whether the reflection is off a metal (Ag, Al, alloy, etc) or because of total internal reflection (“TIR”), the optic relays the source aperture to a virtual or physical plane. Other systems use a combination of reflective, refractive and/or diffusing elements to control distribution.
Narrow full beam angles are difficult to achieve. U.S. patent application Ser. No. 12/788,094, which is hereby fully incorporated by reference herein, describes a reflective optic that exhibits superior beam shaping capabilities and higher efficiencies in a small package. However, in order to achieve high efficiencies at narrow beam angles, the reflective optic becomes relatively large. This may be undesirable in some applications.
Therefore, a small, efficient optic for projecting light into narrow beam angles is needed.